


the road to hell (is paved with good intentions)

by simpleParadox



Category: DC's Legends of Tomorrow (TV)
Genre: Alternate Universe, F/F, F/M, Fluff and Angst, M/M, Marriage, Time Travel
Language: English
Status: Completed
Published: 2019-08-08
Updated: 2019-08-08
Packaged: 2020-08-13 03:44:27
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,979
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20167603
Author URL: https://archiveofourown.org/users/simpleParadox/pseuds/simpleParadox
Summary: Cassie Green-Constantine goes back in time to save her father before he mysteriously disappears from the timeline. While trying to get to know John they also must stop a powerful villain who's hellbent on ruining time itself. Will Cassie save her father, or will she destroy everything in the process?The is an au of the plot of the newest season of The Flash! So instead of Nora going back in time to save Barry, Cassie goes back in time to save John.





	the road to hell (is paved with good intentions)

**Author's Note:**

> Hello all! As I said in the summary this is an au of the newest season of The Flash! Also Cassie, JJ, Levi, Jeff, and Puck all belong to the constangreen discord server! Thank you so much for making these wonderful characters. Here is a cheat sheet for you all!
> 
> Cassie Green-Constantine: John and Gary's adopted daughter.  
JJ Green- Gary's oldest brother.  
Levi Green- Gary's youngest brother.  
Jeff Green- Gary's father.  
Puck- Jeff's partner. 
> 
> I hope you all enjoy this fic!

Cassie had always wanted to see her parents wedding. She knows that most kids don't get that, but she wanted to anyway. There was a wall in their house dedicated to pictures of that day, and as a child Cassie found herself staring at them from time to time. The smile Gary had, stretched to practically his ears, in every photo taken. The tears in John's eyes as he stood at the end of the aisle, waiting for him. The Legends absolutely smashed at the reception. She wished she could've been there, to cheer on the people who saved her life. 

The fact that she was there now was actually insane. She was used to time travel, Gary was a time agent, after all. Not something you could easily hide from your child. But this has always been off limits. The time before John Constantine disappeared. Concrete, Gideon had told her. It had settled and trying to fix it would make too many cracks. 

But there were new developments. And Cassie just, well, she didn't care. She needed to save her Dad. First stop, the Green-Constantine wedding.

She had planned it out, everything she needed to do to save her Father. She had heard the story many times from Gary. Cassie was ten when John disappeared. Only a year after they both had rescued her. The memories of him had started to fade over the years and she hated herself for that. Gary tried to help, telling her the amazing adventures of John Constantine, but they always made me cry by the end of it. So she stopped asking. 

"Mind passing these around?" Cassie was pulled from her thoughts as anther caterer handed her a tray full of champagne. Cassie was currently dressed in the caterers uniform, white button down with a black vest. This was the first step of the plan. Infiltrate herself in the legends lives without revealing herself, if she could. Gideon would obviously know who she was once aboard the ship, but she hoped with some persuasion the AI would be able to keep that information to herself. 

Cassie nodded and took the tray. She stumbled a bit as she started to walk (curse that Green clumsiness) but was able to quickly catch herself. The wedding was held in her Grandfather's backyard. He and Puck had been able to retire to a vary spacious house with enough backyard for, at the time, potential grandchildren. With Puck's (her Grandfather's partner) green thumb, the backyard looked more look like the botanical gardens, which made it the perfect spot for a wedding. 

Everyone was mingling around the area, waiting for the ceremony to start. She handed out glasses to her Uncle JJ, who was talking to Ray about his latest adventure in the rain forest. JJ was a fairly popular wildlife blogger, and had over two million subscribed to him on YouTube. JJ is a fun guy, but can get...a little wild for a lack of a better world. 

Her other Uncle, Levi, took another glass, laughing with Mick as the pyro told him that he stole one of his paintings once. Levi didn't care, in fact he was complimented by it. Levi was a well renowned artist, and most of his pieces sold for thousands of dollars. The Green's were certainly an interesting bunch.

She gave her last glass to Sara, who had found a seat next to Ava. She smiled fondly at them. They looked so young. 

She had been avoiding look at John this whole time. He was talking with the rabbi, not doubt saying some wildly inappropriate things. Cassie just worried that once she saw him, she would lose it. Instead she took a deep breath and headed over to the bar to find the whiskey. She found a well aged one and put some in a tumbler and back on her tray. Here goes nothing, she thought to herself. 

John had stopped talking to the Rabbi and instead stood there by himself as people started to get seated. He was fidgeting with his cuff links, staring at the ground. For once he wasn't wearing his famous trench coat and red tie, instead trading that in for a nice black tie suit. He looked great, but he also didn't look like himself. It was strange, considering most of Cassie's memories of him were only pictures. 

"Nervous?" she asked as she approached him.

John seemed surprised by the sudden quickly and snapped his head up towards her. "Uh, guess you could say that," he smiled, but it didn't reach his eyes. "'Spose that make me a shitty husband, huh?"

Cassie laughed, because all Cassie ever heard was praise from Gary about how good to him John was. "No, I wouldn't say that. I think everyone's nervous on their wedding day."

John nodded, stuffing his hands in his pockets. "You married?"

"Oh no. But my Aba showed me a lot of romantic comedies as a child," Cassie told him.

"Aba?" John raised an eyebrow. 

"Oh, it's Dad in Hebrew. My Dad is also Jewish," she explained, nodding towards the Rabbi. "Anyway, a little birdie told me you liked whiskey, figured that would make you look less like nervous wreck."

"Is it really that obvious?" John laughed, taking the whiskey from the tray. She saw him start to relax a bit, shoulders less tight, as he gulped down the whiskey. 

"Unfortunately," she giggled, taking the empty glass from him. 

"Well, thanks for the help..."

"Cassie," she told him. 

"Cassie," he smiled, as if he liked the name. 

Cassie started to turn to walk away before she got a touch braver. "It's gonna be fine, you know?"

"I know. If I didn't, I wouldn't be here," he told her sincerely, his eyes lighting up as if looking towards the future. Ironically, he actually was. Cassie gave his shoulder a quick squeeze before heading back towards the other caterers. She released a shaky breath she didn't know she was holding in, and let her eyes shudder closed for a second. It was like years of build up had exploded out of her, all those fantasies of seeing her father again fading away to now be replaced with a memory. The feeling was almost too much for Cassie to bear. 

Soon, everyone got into their places and the music started to play. Cassie stood back, but made sure she got the best view of everything. Her parents were getting married for fucks sake. She needed to see every detail of it. 

Grandpa Jeff was the one to walk Gary down the aisle. He was wearing a blue suit, not unlike the ones Cassie saw him wear to work every day. But this one had a patterned lining and he was wearing a patterned bow tie to match. A very Gary thing to do. Both John and Cassie loved it. 

Ava and Sara were up there too. Ava was Gary’s best woman and Sara was John’s. Cassie remembered Gary telling her how happy he was that Ava wanted to be in the wedding that he actually fainted at work. 

Cassie didn’t realize she was crying until they started doing their vows. Someone next to her handed her a tissue and she lifted her hand to her face to feel the wetness of tears. 

“Do you know them?” she asked as Cassie took the tissue from her. 

“Uh, yeah, kind of,” she tried to say, and she wiped her tears and watched as her parents said “I do”. 

The reception was a lot more wild than Gary ever told her. There were at least seven broken items and way too many uses of powers to be quite honest. Gary always told that she should keep her magic on the downlow and only ever use it in case of emergencies. She couldn’t wait to go back to Aba and say she saw him use a spell to refill his shot glass. 

Not that her Aba even knew she was here. If he ever found out, she would be in deep, deep shit. 

Cassie tucked her long, curly hair behind her ears and just watched her family fondly. She wanted to remember every second of this. 

\-------------------------------------------------------------------------------------------------------------------------

Cassie didn’t try to interact with them until a month later. She had timed it exactly. The first appearance of Void and one of his minions. Central city. 

From what she remembered from her few visits to The Flash Museum, this was the time where Barry and the gang were fighting a villain named Cicada. Hence why The Legends were called in to handle this problem in Central City. They were a little preoccupied. 

A demon named Kekio had possessed a businessman and was currently attempting to destroy the city. No poetics like Neron. Just pure destruction. Cassie planned to stay out of this one. Just to watch and make sure everything was fine. 

Except everything wasn’t fine. Gary told her that he and John were able to exorcise Kekio and save the man who he was possessing. But from where Cassie was watching from behind a wrecked car, they were both struggling to keep this demon where he was. 

Cassie looked around. Void was there, watching and she knew it. Nate was the one to spot him right behind he disappeared. But was wasn’t anywhere in her sight. 

“What’s happening?!” Sara asked through the sounds of the raging winds. 

“The demon is much stronger than I anticipated!” John explained, hands outstretched trying to keep the demon in place. “I-I’m not sure Gary and I can do this by ourselves!”

Fuck. Fuck. Has she already screwed up the timeline by just being there? This was supposed to be a breeze! Why were they having such a hard time?

Gary took a few steps forward, hands also outstretched, trying his hardest to get this abomination to leave this poor man’s body. Kekio just smiled and swing a hand, throwing a loose tire at Gary. He yelled and flew backwards, pinned by the tire. 

“Fuck this,” Cassie said to herself. She wasn’t going to watch another parent leave her. “Kekio!” 

Cassie stepped out from behind the car and pointed a finger at the demon. Kekio’s borrowed eyes turned black and he smiled. 

“Oh, and who are you?” he laughed, interest piqued. 

“The girl that’s gonna send your ass back to hell.” Cassie took a few more steps towards Kekio and recited the words from her father’s journal. The words she practiced every day until it was ingrained in her memory. 

As she did this, John stared at her in recognition. It didn’t last long though, as he joined her in reciting the exorcism. Kekio’s wicked smile turned into a scowl and he started yelling. 

“No! No!” he screamed as light enveloped him. Cassie and John started chanting louder.

Soon, Kekio shot out of the man’s body in a form of black smoke and descended back towards hell. The man fell to the ground, unconscious. John looked at her in shock just before heading towards Gary to make sure he was okay. 

She started getting closer to them before Sara stepped in front of her. “And you are?”

Cassie froze. She didn’t intend for things to be like this. She was supposed to be recruited, supposed to slowly gain their trust. This threw her plan out of the window. She took a deep breath. If she told them now, then maybe, just maybe, she would get the family she never had. At least for a little while. 

Gary sat up as Nate pulled the tire off of him. “Weren’t you at our wedding? What the hell’s our caterer doing here?!” 

“I-I,” Cassie gulped as all eyes were on her. “I’m Cassie. Your daughter.”

John and Gary’s eyes widened at her before Cassie heard Charlie break the silence. 

“What the fuck?!”


End file.
